Designing the User Interface is intended primarily for designers, managers, and evaluators of interactive systems. It presents a broad survey of designing, implementing, managing, maintaining, training, and refining the user interface of interactive systems. The book's second audience is researchers in human-computer interaction, specifically those who are interested in human performance with interactive systems. These researchers may have backgrounds in computer science, psychology, information systems, library science, business, education, human factors, ergonomics, or industrial engineering; all share a desire to understand the complex interaction of people with machines. Students in these fields also will benefit from the contents of this book. It is my hope that this book will stimulate the introduction of courses on user-interface design in all these and other disciplines. Finally, serious users of interactive systems will find that the book gives them a more thorough understanding of the design questions for user interfaces. My goals are to encourage greater attention to the user interface and to help develop a rigorous science of user-interface design.